Hi, I'm new to the forum and my recently purchased XJS, and I wonder if some more experienced owners could help point me in the right direction.

I have been trying over the last month of ownership to eliminate a steering wobble on the car. The car feels slightly "loose" at the front at all speeds, but on motorway driving, any speeds over 50mph plus, the front seems to wobble and vibrate quite alarmingly. I was told by a mechanic at the time of purchase that it was a sticky calliper, but I have now been through the following.

New front brake discs and pads
New front callipers
New steering rack bushes
New roll bar links and bushes
New rear gearbox mount
New front subframe Vee bushes

I have new round front subframe bushes to fit.

The car has also had new tyres which have been balanced, re-balanced and then balanced again, but still the wobble is there.

It does seem to me that there is a slight knocking coming from the front, and that driving over slightly bumpy surfaces, I get a lot of knocking and feedback through the wheel.

All other bushes have been replaced for poly bushes approx 1500 miles ago before I bought the car, and I can only assume that they have been fitted correctly. The car apart from this wobble is superb, but I am struggling to find the cause of this vibration.

Can any one help throw some light on this issue please?

Best
Paul

 

Track rod ends?
Steering column universal joint?
Can't think of anything else at the moment.

 

I presume "all other bushes" includes upper and lower control arm bushings, yes?

Have the ball joints been checked for sloppiness?

I was wondering about a bent wheel. Presumably someone would've looked for that during the tire balancing but you never know. Worth checking, I'd think.

Cheers
DD

 

I'll add wheel bearing to Doug's list.

Jack up the front then the back car and hold top and bottom of the wheel and wobble it. there should be almost no movement.

 

Poly bushes in the front wishbones have a tendancy to make the car squeak and rattle more. I know I will be removing my poly wishbone bushes when I re-do the front springs.

 

Good call. I meant to mention bearings.

Again, one might presume that the bearings were repacked and adjusted when the brake rotors were replaced, but.....were they?

Cheers
DD

 

+1 - My front bearings had spun on the stub axle and this caused both front wheels to run untrue. I also had a wobbly rear bearing.

 

In no particular order, assuming all the things you have done so far are OK, and all the things suggested so far are done, it would seem it has to be one of these:

Front shockers,
Stub axles need renewing,
Worn rack,
Full alignment check (camber, castor, etc), including first renewing bottom wishbone bushes as well as top ones before alignment,
Subframe control, renew V mounts and six shot mounts
Subframe integrity (rust)

You also mentioned: "It does seem to me that there is a slight knocking coming from the front, and that driving over slightly bumpy surfaces, I get a lot of knocking and feedback through the wheel." This is a possible symptom of a worn stub axle allowing the bearings to knock, or of a worn lower wishbone bush allowing the pin to knock onto the subframe. It is also a worn rack symptom. Also poly bushes on the top wishbone can induce shimmy at certain speeds, so as someone else mentioned, good idea to return to OEM.

Greg

 

thanks everyone.

to my knowledge, the following poly bushes had been fitted from the paperwork I received with the car
top suspension bush x4
lower wishbone bush x4
anti roll link bush x 8
radius arm bush Lge x 2
radius arm bush Sml x 2
top front shock bush x 4
Steering rack bush kit x 1
anti roll bar bush x 2
anti roll bar bush x 2

I have been told that the bearings were checked and repacked when I swapped the discs over last week, also the ball joints seem in good condition

thanks for your advice so far

 

At this point, were I in your shoes, I'd seriously investigate the possibility of a bent/damaged wheel before doing anything else.

Just my 2-cents


Cheers
DD

 

Honestly though, a bent wheel won't cause loose steering. With poly bushings it should be tight!

 

But a bent wheel could certainly account for the wobbble and vibration mentioned in the original post, and a "wobble/vibration" could possibly be felt as "looseness".

<shrug>

There are many ways to approach a problem, of course. When facing a vibration/wobble problem, which seems to be the primary complaint in this case, positively eliminating tires/wheels as a possibility is usually a pretty good first step

Cheers
DD

 

I would agree with it being the wobble source, old wheels are pretty prone for sure.